External power supply system

1. An external power supply system comprising: an electrical storage device; a motor including stator coils connected to a neutral point, the neutral point being an output node from which electric power from the electrical storage device is supplied to an external device; an inverter configured to drive the motor by using the electric power of the electrical storage device, the inverter including a first switching element and a second switching element connected in series with each other between a positive electrode power supply line and a negative electrode power supply line, a connection node of the first switching element and the second switching element being connected to a corresponding one of the stator coils; and a control unit configured to control the inverter, the control unit being configured to input driving signals to the inverter so as to drive the inverter such that a voltage at the neutral point becomes a predetermined value, the control unit being configured to compensate for the driving signals in a dead time period, which is a period in which off-state driving signals are supplied to the first switching element and the second switching element, on the basis of a current that is input from the connection node to the corresponding one of the stator coils or output from the corresponding one of the stator coils to the connection node while an engine is driven.

2. The external power supply system according to claim 1 , wherein the stator coils include a U-phase coil, a V-phase coil and a W-phase coil of which one ends are connected to the neutral point, the connection node of the first switching element and the second switching element is connected to the other end of the U-phase coil, the inverter further includes a third switching element, a fourth switching element, a fifth switching element and a sixth switching element, the third switching element and the fourth switching element being connected in series with each other between the positive electrode power supply line and the negative electrode power supply line, a connection node of the third switching element and the fourth switching element being connected to the other end of the V-phase coil, the fifth switching element and the sixth switching element being connected in series with each other between the positive electrode power supply line and the negative electrode power supply line, a connection node of the fifth switching element and the sixth switching element being connected to the other end of the W-phase coil, and the current that is input from the connection node to the corresponding one of the stator coils or output from the corresponding one of the stator coils to the connection node includes a current flowing through the U-phase coil, a current flowing through the V-phase coil and a current flowing through the W-phase coil.

3. The external power supply system according to claim 1 , wherein the control unit is configured to repeatedly compensate for the driving signals on the basis of an error one period before in an output voltage at the neutral point while the engine is not driven.

4. The external power supply system according to claim 1 , wherein the control unit is configured to compensate for the driving signals in the dead time period when one of an output voltage of the inverter and a carrier frequency of the inverter is changed while the engine is not driven.

5. The external power supply system according to claim 1 , further comprising: a second motor and a second inverter, wherein an external load is connected between the neutral point and a second neutral point, the second neutral point is a neutral point of stator coils of the second motor, and the control unit is configured to compensate for the driving signals in the dead time period when a voltage share between the inverter and the second inverter is changed while the engine is not driven.

6. The external power supply system according to claim 1 , further comprising: an engine, wherein the motor is configured to be able to generate electric power upon reception of mechanical power from the engine.

7. An external power supply system comprising: an electrical storage device; a motor including stator coils connected to a neutral point; an inverter configured to drive the motor by using the electric power of the electrical storage device, the inverter including a first switching element and a second switching element connected in series with each other between a positive electrode power supply line and a negative electrode power supply line, a connection node of the first switching element and the second switching element being connected to a corresponding one of the stator coils; and a control unit configured to control the inverter, the control unit being configured to input driving signals to the inverter so as to drive the inverter such that a voltage at the neutral point becomes a predetermined value, the control unit being configured to compensate for the driving signals in a dead time period, which is a period in which off-state driving signals are supplied to the first switching element and the second switching element, on the basis of a period of the neutral point output voltage harmonic which is calculated from a rotation angle of the motor, while an engine is driven.